L3 overview of thermography test

OML751 TESTING OF MATERIALS
ME8097 NON DESTRUCTIVE TESTING
AND EVALUATION
M.KARTHIKEYAN
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
AAA COLLEGE OF ENGINEERING & TECHNOLOGY, SIVAKASI
karthikeyan@aaacet.ac.in

UNIT I OVERVIEW OF NDT
1. NDT Versus Mechanical testing & Overview of Liquid penetrant
test
2. Overview of Magnetic particle test
3. Overview of Thermography test
4. Overview of Eddy current test
5. Overview of Ultrasonic test
6. Overview of Acoustic emission test
7. Overview of Radiographic test
8. Various physical characteristics of materials and their
applications in NDT.,
9. Visual inspection – Unaided and aided.

THERMOGRAPHY TESTING
INTRODUCTION:
 Thermography is a non-contact, non-destructive testing method.
 Used in the aerospace, defense and general engineering
industries to detect flaws in a variety of structures.
 Thermographic inspection can be used over a large area.
 Can detect a range of defects, including: Voids, Delaminations,
Corrosion, Porosity, Crack Propagation and Impact Damage.

TYPE 1
Every object with a temperature above the absolute zero point
(-273 °C) will emits infrared (IR) radiation.
But the human eye cannot identify this infrared (IR) radiation
due to its wavelength.

 Thermal imager can detect this IR.
 Its central element, the detector, is sensitive to IR radiation.
 Based on the intensity of the IR radiation, it determines the
temperature of the object's surface, and makes it visible for the
human eye with a thermal image.
 This process is referred to as thermography.
THERMAL IMAGER

 In order to make the IR radiation visible, the detector records
it, converts it into an electric signal, and gives each signal a
certain colour which is then shown in the display of the thermal
imager.
 In principle, thermal imagers thus translate wavelengths from
the infrared spectrum into wavelengths which are visible to the
human eye (colours).
INFRA RED
THERMOMETER

TYPE 2
 The basic principle of thermographic NDT is that the flow of
heat from the surface of a solid is affected by internal flaws
such as disbonds, voids or inclusions.

TYPES
1. PULSED OR FLASH THERMOGRAPHY TEST
2. LOCKIN – THERMOGRPAHY
3. BURST VIBRO THERMOGRAPHY
4. LOCK IN VIBRO RHERMOGRAPHY

PULSED OR FLASH THERMOGRAPHY TEST

 Pulse thermography is a non-destructive technique used to find
defects in aircraft and aerospace components.
 Pulse thermography allows materials to be inspected very
quickly for near-surface defects and bonding weaknesses.
 In pulse thermography the material to be inspected is heated
up equally using a very short heat pulse.
 Defects, bonding faults and corrosion can be observed using a
thermographic camera on the surface.

LOCK IN VIBRO RHERMOGRAPHY
SONIC WAVES – DEFECT – DISTURB
– VIBRATION ENERGY INTO HEAT

BURST VIBRO THERMOGRAPHY
SONIC WAVES – DEFECT – DISTURB
– VIBRATION ENERGY INTO HEAT

ADVANTAGES
 Large areas can be scanned fast.
 Thermography is an area investigating technique, whereas
most of the other non-destructive methods are either point or
line testing methods.
 This results in major savings in time, people, work and
machinery.
 Thermographic device is risk-free, as it does not emit any
radiation;
 It shows a visual picture so temperatures over a large area can
be compared
 It is capable of catching moving targets in real time.

 It is possible to predict the failure by observing the
temperature.
 It can be used to measure or observe in areas inaccessible or
hazardous for other methods.
 IR cameras are relatively easy to use.
 Large electrical cabinets and whole electrical installations can
be quickly scanned.
 The exact location of the potential problematic point can be
easily determined.

LIMITATIONS
 It is not possible to penetrate in extended depths (only a few
mm's).
 To interpret the results requires a certain experience and
knowledge.
 Quality cameras often have a high price range

APPLICATIONS:
 They are used by the police and military for night vision,
surveillance, and navigation aid;
 by firemen and emergency rescue personnel for fire
assessment, and for search and rescue;
 by the medical profession as a diagnostic tool; and
 preventative maintenance,
 processes control and
 nondestructive testing.

 defects in composite
 It can be used to find defects in shafts, pipes, and other metal
or plastic parts.
 It can be used to detect objects in dark areas.
 It is capable of catching moving targets in real time.
 It is possible to predict the failure by observing the
temperature.
 It can be used to measure or observe in areas inaccessible or
hazardous for other methods.
 Used in the aerospace, defense and general engineering
industries to detect flaws in a variety of structures.
 Can detect a range of defects, including: Voids, Delaminations,
Corrosion, Porosity, Crack Propagation and Impact Damage.

Typical problems in electrical installations that can be detected
with infrared thermography include:
 Connections that are loose, poorly installed, corroded etc.
 Unbalanced loads.
 Defective equipment.
 Undersized conductors.
 Overheated motors.
 Overloaded circuits.
 Potential fire hazards.
 Worn components.
 Thermal abnormalities in batteries.

Infrared Thermography is ..
1. a graphical representation of heat
2. an accurate measurement of temperature
3. a photographic representation of heat
MCQ - 1

Every object with a temperature above …….. will emits
infrared (IR) radiation.
1. 0°C
2. 300°C
3. 100°C
4. -273 °C
MCQ - 2

Wavelength of the is infrared (IR) radiation is
1. 550 nanometer
2. 580 nanometer
3. 600 nanometer
4. 450 nanometer
MCQ - 3

Ultrasonic waves are used in case of
1. LOCKIN – THERMOGRPAHY
2. PULSED OR FLASH THERMOGRAPHY
3. VIBRO THERMOGRAPHY
MCQ - 4

Infrared thermometer is superior to thermal imager
1. True
2. False
MCQ - 5

PART - A
1. Define thermography
2. What are the applications of thermography test?
PART - B
1. What are the methods available for checking in thermography?
Explain any one method
QUESTIONS

L3 overview of thermography test

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